A button for adding data is displayed multiple times. An error occurred while adding the data. Solution

A button for adding data is displayed multiple times. An error occurred while adding the data. Could you tell me how to deal with this problem, whether to let them not submit the form repeatedly, or how to do it? for more details, see ., Very simple. let's look at the example & lt; formaction = 'A. php 'method = 'post' on a button for adding data. multiple times, an error occurred while adding the data on the page.
How can I solve this problem,
Is to keep them from submitting forms repeatedly,
How can I do this,
For more information, see.

------ Solution --------------------
Simple. let's look at the example.


As long as the form action is changed to # After the token is submitted for the first time, it cannot be submitted for the second time.